Optical cable with electromagnetic field shield layer

An optical cable comprising;

• a cable body including a first end, a second end and an inner surface defining a passage within the cable body;
• an elongate optical transmission element located within the passage and extending between the first end and the second end of the cable body;
• an elongate metal wire located within the passage and extending between the first end and the second end of the cable body;
• and
• an electromagnetic shielding layer located within the passage surrounding the elongate metal wire, wherein at least a portion of the electromagnetic shielding layer is located between the inner surface of the cable body and the elongate metal wire, wherein the electromagnetic shield layer comprises a helically wrapped strand extending between the first end and the second end of the cable body;
• wherein the helically wrapped strand includes a non-metallic core strand supporting a metal material;
• wherein the helix angle of the helically wrapped strand varies along a longitudinal axis of the cable.

A shielded optical cable comprising:

• a cable body including a first end, a second end and an inner surface defining a channel within the cable body;
• an optical transmission element located within the channel;
• an elongate electrical conductor located within the channel;
• and
• a plurality of elongate strands each including a metal material, wherein the plurality of elongate strands define an electromagnetic shield layer surrounding a portion of the channel in a circumferential direction that includes the optical transmission element and the electrical conductor;
• wherein the shield layer includes a plurality of gaps defined between the plurality of elongate strands such that between 20% and 80% of a surface area of the radially outward facing surface of the shield layer is occupied by the plurality of elongate strands;
• wherein at least one of the plurality elongate strands is helically wrapped around the optical transmission element and the electrical conductor;
• wherein the helix angle of the helically wrapped elongate strand varies along the longitudinal length of the cable.

A method of forming an electromagnetically shielded optical communication cable comprising:

• providing an elongate optical transmission element;
• providing an elongate metal wire;
• forming an electromagnetic shield layer around the elongate metal wire by wrapping an unbraided strand containing a metal material in a helical pattern around the elongate optical transmission element and the elongate metal wire, wherein the step of forming the electromagnetic shield layer includes varying the helix angle of the helical pattern as the unbraided strand is wrapped around different portions of the elongate metal wire, wherein the metal material acts to limit electromagnetic fields from traversing across the electromagnetic shield layer;
• and
• forming a cable body around the electromagnetic shield layer, the elongate optical transmission element and the elongate metal wire.